1. Field of the Invention
The present invention relates to a digital/analog (D/A) converter of a switched capacitor circuit type used in a multi-level D/A converter which is incorporated into a multi-bit ΔΣ D/A converter or a multi-bit A/D converter.
2. Description of the Related Art
In a prior art D/A converter of a switched capacitor circuit type, including at least one capacitor, at least one power supply terminal, and at least one output terminal, a switch circuit is adapted to carry out a charging operation upon the capacitor so that a charge is stored in the capacitor and then carry out a discharging operation upon the capacitor to discharge the charge to the output terminal in accordance with a digital input data signal (see: JP-9-307447-A). This will be explained later in detail.
In the above-described prior art D/A converter, if the D/A converter is incorporated into a multi-level D/A converter, even after a discharging operation is carried out, a charge in a capacitor stored during a charging operation may not be completely discharged, which would change the settling error. As a result, the total harmonic distortion (THD) characteristics and the signal-to-noise ratio (S/N) characteristics would be degraded. This also will be explained in detail later.